Controllable pitch propeller



Sept. 2, 1952 A. H. LOCKHEED 2,609,056

CONTROLLABLE PITCH PROPELLER Original Filed June 25, 1941 1 3 Sheets-Sheet l F a 3 M 4 37 -4 13 ALLAN H. lack/Iss0, 13 INVENTOR.

IIW

.9 ATTORNEY.

P 1952 A. H. LOCKHEED 2,609,056

CONTROLLABLE PITCH PROPELLER Original Filed June 23, 1941 5 Sheets-Sheet 2 ALLA/v Zack/{E5 INVENTOR.

ATTORNEY.

p 1952 A. H. LOCKHEED 2,609,056

CONTROLLABLE PITCH PROPELLER Original Filed June 23, 1941 3 Sheets-Sheet 5 ALLA/Y H [OCAf/EED,

lNVENTQR.

ATTORNEY.

Patented Sept. 2, 1952 UNITED STATES PATENT. OFFICE Allan H. Lockheed, Los, Angeles, Calif.

I Substitutedforabandoned application Serial No.

399,273, June 23, 1941. This application any 4, 1945, Serial No. 571,229

4; Claims. (01. 110460.29.)

llhisv application is a. substituteior; applicants prior application, Serial No. 399,273, filed June 23'; 1941; which became abandoned April 3, 19414.

This invention relates to, controllablepitch propellers of the general class: of screw propellers in whichtheinclination of the blades maybevaried or-adjusted,

Although this propeller is primarily designed for aviation use it may be adapted for marine propellers or for fans or for any of that general type of device.

The objecta-ndfunction of a controllable pitch propeller,- is well known in the art and doesv not need to be herein elaborated upon. It is suiiicient to.say" that in aviation-use it is desirable tohave-the propeller adjusted with low pitch for increased engine speed and power as for takin ofl= and in climbing and to have the blades adjusted with high pitch ior'normal flying.

Theobjectofthis invention is tov provide a simplified construction which will be strong and dur-' able andparticularly one which occupies a mini mum of space and is simply operated. The device is provided with various novel features of construction and arrangement as hereinafter more fully describedand particularly pointed out in the claims, reference being had to the accompartying-drawings; in which Fig; 1' is: anelevation of the forward part of the fuselage ofan. airplane showing a part of the engine-in outline, with thecontrollable pitch propeller mounted on the engine shaft and: with a part of the pitch actuating mechanism mounted on the propeller-hub.

Figp2 is anenlarged view of the hub of the propeller'and a part of theactuating mechanism with parts broken away in difierent planes to illustrate details of construction.

Fig. 3 :is a cross-section. on the line 33 of Fig. 2 showing-the propeller and its hub inrelevation.

Fig. is a cross-section on the line 4-4 of Fig. 2 illustrating details of construction and particularlyaone-Way roller clutch mechanism.

Fig. 5 is: across-section on the line55 of Fig. 2- illustratingthe brakemechanism.

Fig; filis: a section through the hub on the line 6MB of 'Fig. 2 -illustrating the worm andgear-actuating mechanism.

Fig; 7" is a longitudinal section of the safety clutch illustrated in'Fig; 1.

Fig. 8" is a fragmentary view ofa second form of operating mechanism. v

Fig; 91s a fragmentarysection illustrating that part of the second form of actuating mechanism whichisloca-ted upon the propeller hub.

J anu- Fig. 10 is alongitudinal section of thedriving shaft, safety clutch, one-way clutch and brake illustrated in Fig. 8-.

Fig. 11 is a cross-sectionof the one-way clutch deviceon the line H-- ll of Fig. 10.

Describing first that form of, structure illus trated in Figs. 1 and 2 and other; partial views, the nose section I of the fuselage ofan airplane has a conical shield or spinner 2 fixed to the propeller and rotating with it and carried by a conventional engine 3 shown in outline. The engine shaft 4 (Fig. 2) projects forwardly from-the engineand has the propeller hub 5 fixedto it in. a conventional way as by a key Sand a nut 1.

The-hub 5;h as radially extending blade-sockets 8- corresponding in number tov the number of blades, two being shown. The inner endsSof the propeller blades [0 are received in the sockets 8 and are rotatably retained by suitablebearings suchas ball bearings ll spacedby sleeves IZand retained by suitable structure such as a cap 13.

The extremeand inner end of each blade is provided with, aplate [4 rigidly fastened to it-by screws l5 and provided on a portion of its periphery with-gear teeth It (Fig. 6) meshing with worm gears 11. Each respective worm gear-I1 is-proe vided with a shaft 18, journaled in bearings provided; in the. hub socket 8 and they are retained inplace by suitable structure such as a sleeve-l9 held in place by screws. One, endof each shaft is rojectsfromtherear side ofthe propeller hub and is. provided with a pinion gear 20.

Rotation of the gears 20, the shafts l8=andi the worm gears I! will cause rotation of the. respective propeller blades. on axes radial to the axis of the shaft 4, this blade, rotation being limited in each directionby a stop pin 2| fixed to the. base of. the socket 8. andprojecting into a notch or recess 22 in the. periphery ofithe. plate: [4' so that the rotation of the blades on their axes is limited.

Thezrotation of the blades on their axes changes thepitch of the propeller. The limit ofmovement. is controlled by the said pin 2| in'the notch 22, being setv for extreme high pitch in one position and extreme low pitch in the other position.

The'aforedescribed mechanism is identical in eachof' the two forms of" operating mechanism disclosed herein,

A gear 25 meshin with both pinions- 20 has a hub 26 rotatably mounted upon the propeller-hub 5, this hub 26 having a continuation 2:600 fixed-to itwhich is provided with a brake drum 2l. A circular brake shoe 28 is split andexpansibleand anchored to astationarypart of the engine at 29 (Fig. 5) and providedwith-abrakelining 30 10'- cated within the brake drum 21 and is expanded for braking action by suitable means such as a wedge 3| inserted at its split part and manually actuated by a lever 32 (Fig. 2) which may be controlled from a suitable location such as the pilot's cockpit.

A gear 35 (Fig. 2) surrounds the hub 26 of the gear 25 and is mounted for free rotation thereon by a ball bearing 33. Rollers 31 constituting a conventional one-way clutch are interposed between the gear 35 and the hub continuation 23a, which is fixed to and rotated with the hub 25 of the gear 25, so that free relative rotation may be had between the gears 25 and 35 in one direction but the gears will be clutched together by the rollers 31 in attempted relative rotation in the opposite direction and particularly in the present instance when the gear 35 is rotated faster than the gear 25 the clutch will act to positively drive the gear 25 with the gear 35.

Frictional resistance to movement of the gear 25 on the propeller hub 5 is obtained by a collar 38 (Fig. 2) fixed to the propeller hub 5 adjacent the gear hub continuation 25a. and a spring pressed plate 39 adjacent the front face of gear 25, suitable friction disks 40 being interposed. The springs 4| act to squeeze the hub of the gear 25 against the fixed collar 38 locked by a set screw 38a and to frictionally resist its movement relative to the propeller hub 5.

The gear 35 meshes with a bevel gear 45 fixed to a shaft 46 journaled in a bearing 41 mounted on the engine. 3, this shaft being connected by a flexible coupling or universal joint 48 to a shaft 49 journaled in a bearing 50 mounted on the engine. A small electric motor 5| is mounted on the engine and has its shaft 52 in alignment with the shaft 49 and connected thereto by a safety friction clutch 53 (Fig. 7) which comprises a disk '54 fixed to' the housing 55 and a head 56 and collar 51, both on the shaft 52, and located upon opposite sides of the disk 54 and held into frictional engagement therewith by a spring 58 bearing against nuts 59. This safety clutch transmits power under normal conditions but will slip when overloaded.

The operation of the first form of structure is as follows: In normal operation of the propeller the blades are set to either extreme high pitch or extreme low pitch within the limits controlled by the stop pin 2| in the notches 22. In these positions the inherent irreversible character of the intermeshing worm I! and gear teeth |5 tends to lock the blades in their adjusted positions and to prevent inadvertent movement. A further lock is provided by the frictional resistance to rotation of the gear 25 on the propeller hub 5 by the spring pressed plate 39 squeezing its hub against the fixed collar 38, the gear 25 meshing with the pinions 20 on worm gear shafts 8. With the propeller rotating, when it is desired to move the blades l to change their pitch in one direction the lever 32 (Fig. l) is operated to apply braking resistance to the brake drum 21 which is connected to the hub of the gear 25 and when this braking resistance is greater than the frictional resistance caused by the spring pressed plate 39 the gear 25 will be slowed in its rotation relative to the propeller hub and caused to rotate upon the propeller hub 5 at a speed less than the speed of rotation of the hub and this relative movement will be transmitted to the pinion gears 2|] which will rotate the worm gears l1 causing the blades ID to change their pitch and inasmuch as there is no mechanism provided to indicate the extent of this movement it is presumed that this change of pitch will continue until the stop pin 2| prevents further movement of the blades which will cause the brake shoe 28 to slip on the brake drum 21.

The opposite adjustment of the blades is accomplished by actuation of the motor 5| and may be done either when the propeller is at rest or while it is rotating. To accomplish this adjustment the motor is energized and through its various heretofore described connections it will rotate the gear 35 in the same direction as, though momentarily just a little faster than, the normal rotation of the propeller hub and in this direction of rotation the rollers 3! will act to clutch the gear 35 to the gear 25 causing it to rotate in the same direction as the propeller thus rotating the pinion gears 20 and the worm gear H to move the blades In.

The motor 5| must mave sufiicient speed so that it can drive the gear 35 faster than the rotation of the shaft 4 and the propeller hub 5 and it must have sufficient power to overcome the frictional resistance to rotation of the gear 25 caused by the spring pressed plate 39. It also must turn in the proper direction to drive the gear 35 in the same direction as the rotation of, the shaft 4.

The safety clutch 53 is to permit slippage when the blades have reached the limit of their adjustment and the motor 5| continues to rotate. This safety clutch also acts to prevent damage to the motor 5| in case of a kick-back of the engine which sometimes occurs.

In the form of structure illustrated in Figs. 8, 9, l0 and 11 the gears 25 and 35a are integrally formed or rigidly connected together and mounted for rotation on the propeller hub 5 and the gear 25 meshes with the pinions 20 and actuates them to adjust the blades as previously described. The hub 26 of these gears is squeezed between the collar 38 fixed to the propeller hub and the spring pressed plate 39 as and for the purpose previously described.

In this form of structure (Fig. 9) the bevel gear 45 is constantly driven by the gear 35a all of the time that the propeller is rotated. The gear 45 is mounted on a shaft 46 journaled in the bearing 41 and is connected by a universal joint 48 with a shaft 49a journaled in the bearing 50.

A brake drum '60 (Fig. 10) is fixed to the shaft 49a adjacent the bearing 53 and is surrounded by a brake band 6| which is operated to exert braking effort on the drum 60 by a lever 62 which is connected to some suitable device as a cam 63 (Fig. 8) which will contract the brake band 6| upon operation f the lever 62.

A combined safety clutch and one-way clutch is located in a housing 61 (Fig. 10) which surrounds the shaft 49a and is mounted for rotation thereon on a bearing '64. Rollers 65 are interposed between the housing 61 and the hub 65 of the brake drum B0 and act to clutch the housing 61 to the drum 60 upon relative rotation of the two parts in one direction but permits free relative rotation thereof in the opposite direction.

The safety clutch portion of this device corresponds to that shown in Fig. 7 and previously described and serves to connect the clutch housing 61 with the shaft 52 of the electric motor 5|.

In the operation of this form of structure the shafts 45 and 49a (Fig. 8) and the brake drum are constantly rotated during rotation of the shaft 4. However, the one-way clutch rollers 65 are released during normal shaft rotation and the rotation of the shaft 49a is not transmitted to the clutch housing 61 and the motor shaft 52 which normally remain idle. When it is desired to change the pitch of the propeller blade in one direction the brake band 61 is clamped upon the drum 60 which retards rotation of the shaft 49a and transmits this retarding effort to the gears 35a and causing them to rotate on the propeller hub 5 in a direction opposite to the propeller shaft rotation, this rotating movement being transmitted through the pinions 29, the worm gears I7 and the gear teeth [6 to the respective propeller blades.

For adjusting the blades to the other position the motor 51 is energized and when the speed of rotation of the shaft 52, which is connected to the clutch housing 67 by the safety clutch heretofore described, becomes greater than the rotation of the shaft 49a the clutch roller 65 will grip the hub 66 of the drum 60 and cause the shaft 49a to rotate faster than it had previously been driven by rotation of the propeller shaft. This increased rotation will be transmitted through the various connecting parts to the gears a and causing them to rotate upon the hub 5 in the direction of rotation of the hub and rotating the pinions 29 and their connected parts to move the propeller blades to the opposite angle.

I claim:

1. A controllable pitch propeller comprising a hub mounted on a shaft, propeller blades mounted for rotation on axes radial to the axis of said hub, means for rotating said blades on their respective axes including pinions spaced from and rotating on axes substantially parallel to the axis of said hub, a gear rotatably surrounding said hub and meshing with said pinions, a brake to retard rotation of said gear during rotation of the hub, a second gear rotatably surrounding the axis of said hub, a one-Way clutch acting to clutch said second gear to said first gear, and means for rotating said second gear'faster than the rotation of the shaft.

2. A controllable pitch propeller comprising a hub mounted on a shaft, propeller blades mounted for rotation on axes radial to the axis of said hub, means for rotating said blades on their respective axes including pinions spaced from and rotating on axes substantially parallel to the axis of said hub, a gear rotatably surrounding said hub and meshing with said pinions, constantly acting friction means to resist rotation of said gear relative to said hub, a brake to retard rotation of said gear during rotation of the hub, a second gear rotatably surrounding the axis of said hub, a one-way clutch acting to clutch said second gear to said first gear, and means for rotating said second gear faster than the rotation of the shaft.

3. A controllable pitch propeller comprising a hub mounted on a shaft, propeller blades mounted for rotation on axes radial to the axis of said hub, means for rotating said blades on their respective axes including pinions spaced from and rotating on axes substantially parallel to the axis of said hub, a gear rotatably surrounding said hub and meshing with said pinions, a brake to retard rotation of said gear during rotation of the hub, a second gear rotatably surrounding the axis of said hub, a one-Way clutch acting to clutch said second gear to said first gear, and means for rotating said second gear faster than the rotation of the shaft comprising a motor rotatably connected to the second gear.

4. A controllable pitch propeller comprising a hub mounted on a shaft, propeller blades mounted for rotation on axes radial to the axis of said hub, means for rotating said blades on their respective axes including pinions spaced from and rotating on axes substantially parallel to the axis of said hub, a gear rotatably surrounding said hub and meshing with said pinions, a brake to retard rotation of said gear during rotation of the hub, a second gear rotatably surrounding the axis of said hub, a one-Way clutch acting to clutch said second gear to said first gear, and means for rotating said second gear faster than the rotation of the shaft comprising a motor rotatably connected to the second gear and a friction clutch interposed between the motor and the second gear.

ALLAN H. LOCKHEED.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,378,401 Davies May 17, 1921 1,427,178 Turnbull Aug. 29, 1922 1,719,953 Wiegand July 9, 1929 1,776,650 Carter Sept. 23, 1930 1,793,654 Turnbull Feb. 24, 1931 1,799,828 McCauley Apr. 7, 1931 1,857,392 Nixon May 10, 1932 1,875,593 Heath Sept. 6, 1932 2,000,049 Taylor i May 7, 1935 2,007,417 Aivaz July 9, 1935 2,033,342 Lansing et al. Mar. 10, 1936 2,127,687 Heath Aug. 23, 1938 2,138,339 Chauviere Nov. 29, 1938 2,144,927 Lavasseur Jan. 24, 1939 2,131,985 Waseige Dec. 5, 1939 2,306,135 lvlercier Dec. 22, 1942 2,314,025 Waseige Mar. 16, 1943 2,327,217 Reiber et al. Aug. 17, 1943 2,362,914 McLeod Nov. 14, 1944 2,372,667 Forsyth et al Apr. 3, 1945 FOREIGN PATENTS Number Country Date 445,652 Great Britain Apr. 16, 1936 

